Conventionally, a valve arrangement structure of a construction machine including a control valve which is connected to a hydraulic device via a hydraulic pipe and a solenoid valve which is connected to the control valve via a pilot pipe is known (for example, Japanese Patent No. 3273537).
Japanese Patent No. 3273537 discloses a configuration including a multiple valve as a control valve unit which is arranged on a slewing frame via a supporting bracket and a solenoid valve integrally provided in an upper part of a side surface of the multiple valve.
However, with the invention disclosed in Japanese Patent No. 3273537, the solenoid valve is arranged in the upper part of the side surface of the multiple valve and, at the same time, the pilot pipe is routed from the solenoid valve toward the multiple valve in a disorderly manner. Therefore, there is a risk that the pilot pipe routed along the side surface of the multiple valve and the hydraulic pipe connected to the side surface of the multiple valve may become entangled.
In addition, since the pilot pipe expands in a direction perpendicular to an axial direction of the pilot pipe due to force which the pilot pipe receives from oil when oil circulates in the pilot pipe, a large routing space must be secured in consideration of such expansion.